The present invention relates to a magnetic disk apparatus, and particularly to a head suspension and a head assembly used therein.
Recently, to reduce the size and increase the recording density of magnetic disk apparatus, the xe2x80x9cflying heightxe2x80x9d of a head slider over a recording medium has been decreased to an extremely low height, or contact recording and reproduction have been implemented so that the slider remains in contact with the recording medium. The head assembly used in the magnetic disk apparatus requires a gimbal having low rigidity to enable the magnetic head slider to track even in the presence of installation errors of the head assembly or undulations of the magnetic disk, and a suspension or load beam having high resonant frequency in the seek direction, i.e., in the radial direction of the disk, for highly accurate positioning.
Portable personal computers such as notebook computers must have strong shock resistance because they are often carried. Thus, the magnetic disk apparatus for these computers are equipped with a loading and unloading scheme to unload the head slider from the disk surface when the power is off or when the computers go into a sleep mode, and to load the head slider onto the disk surface when in use. Typically, a magnetic disk apparatus equipped with the loading/unloading scheme raises a rectangular tip installed on the front end of the magnetic head assembly onto the ramp inclined portion of a ramp component provided on the outer periphery of the disk medium when the computer power is off or the computer is in a sleep mode, thereby separating the magnetic head slider from the magnetic disk. In this manner, the magnetic head slider can be prevented from hitting and damaging the magnetic disk when the computer receives a shock.
A known gimbal structure which satisfies the demand for low gimbal rigidity and high resonant frequency in the seek direction, supports a head slider on a pivot point. The gimbal is fixed by spot welding to the tip of a load beam, and the magnetic head slider is loaded onto the gimbal. A pair of ribs are formed integrally on both sides of the load beam to increase rigidity. A rectangular tip to be raised onto the ramp component and unload the magnetic head slider from the magnetic disk is formed integrally at the tip of the load beam. The known load beam and gimbal are generally formed from stainless steel. The plate thickness of the load beam is about 43 xcexcm, and that of the gimbal is about 20 xcexcm.
To achieve higher recording density, faster speed, and higher reliability for magnetic disk apparatus, gimbal rigidity must be reduced to stabilize the flying of the magnetic head slider in the magnetic head assembly, and the load beam must have high resonant frequency in the seek direction, i.e., in the radial direction of the magnetic disk. Furthermore, the resilient part of the load beam must have a low spring constant to reduce load fluctuations. There must be at least four printed wires for signal lines when a magnetoresistance effect head (MR head) and a loading/unloading scheme are adopted.
Resonance in the seek direction is normally accompanied by torsion. Thus, at the same time the rigidity in the seek direction is increased, the torsional rigidity must also be increased. A conventional load beam having ribs formed on the rigid part of the load beam has increased flexural rigidity, but the torsional rigidity is not sufficiently high and no different from a flat plate. When the plate thickness of the entire load beam is increased to raise the torsional rigidity, the accompanying increase in mass does not result in an equivalent contribution to an increase in the resonant frequency of the load beam. The increase in the mass of the head assembly also induces a drop in the reliability of the shock resistance.
To stably fly the magnetic head slider over a disk, the gimbal rigidity and the spring constant of the resilient part of the load beam must be decreased and the variations in the load must be minimized. If a load beam has the same thickness as the gimbal, the load beam can be made more rigid by a strategy such as thickening the plate of the load beam. However, lowering the spring constant requires opening a hole in the resilient part of the load beam. If a hole is opened in the resilient part of the load beam, the torsional rigidity of the resilient part is lost, and the resonant frequency drops. The spring constant of the load beam can also be lowered by thinning the resilient part by half etching, but obtaining the desired thickness is difficult.
Low flying sliders used recently in some computers are mostly negative pressure sliders. Therefore, when the slider is unloaded from the top of the magnetic disk, the slider tends to stick to the surface of the magnetic disk. Forcibly pulling offthe slider deforms the gimbal.
Accordingly, one object of this invention is to provide an improved head assembly which enables high recording density at faster speeds.
Another object of this invention is to provide an improved head assembly having a gimbal with low rigidity and a load beam having high resonant frequency in the radial direction of a magnetic disk.
Still another object of this invention is to provide an improved head assembly having a reinforcing plate attached to the load beam.
Yet another object of this invention is to provide an improved head assembly having a gimbal which is not prone to deformation when a slider is unloaded from a disk surface.
Further object of this invention is to provide an improved head assembly having a hook formed on a gimbal to prevent the gimbal from deforming when the slider is unloaded from a disk surface.
In keeping with one aspect of this invention, a head suspension includes a substantially planar load beam, a gimbal extending from and formed integrally with the load beam. The gimbal has a slider loader on which a head slider is adapted to be attached. Also included in the head suspension is a substantially rigid reinforcing plate cooperatively attached to the load beam.
A head assembly of this invention includes a substantially planar load beam, a gimbal extending from and formed integrally with the load beam. The gimbal has a slider loader. A reinforcing plate is cooperatively attached to the load beam and a head slider is fixedly attached to the slider loader.
A disk apparatus of this invention includes a housing, a head assembly provided in the housing and having a head element for reading and writing data on a disk having a plurality of tracks, and an actuator for moving the head assembly over the tracks. The head assembly further includes a substantially planar load beam, and a gimbal extending from and formed integrally with the load beam and having a slider loader. A reinforcing plate is cooperatively attached to the load beam, and a head slider having the head element is fixedly attached to the slider loader.
Another aspect of a disk apparatus of this invention includes a housing with a base, a head slider having a head element for reading and writing data on a disk having a plurality of tracks, and an actuator having an actuator arm rotatably fixed on the base for moving the head slider over the tracks of the disk. A controller moves the actuator for loading and unloading the head slider on and from the disk. A ramp component is fixed to the base for slidably receiving the head slider when the head slider is unloaded from the disk. Also, a head assembly is mounted on a tip of the actuator arm. The head assembly includes a substantially planar load beam, a gimbal extending from and formed integrally with the load beam and having a slider loader on which the head slider is fixedly attached, and a reinforcing plate cooperatively attached to the load beam.